Compact, portable computers are becoming increasingly popular among college students, businesspeople, writers, and others who require portable word-processing, e-mail, and computer graphics capabilities. In particular, notebook-sized computers, commonly known as “notebook computers”, are becoming increasingly popular because their small size and small weight make them portable and convenient to use.
It is desirable to make the notebook computer easy to use, particularly in a variety of locations. For example, many businesspeople use their notebook computer while traveling. Consequently, it is desirable that the notebook computer fit onto a small space, such as an airline seat-tray. Preferably, a notebook computer is also compact enough to be easily carried, such as in a briefcase or a piece of luggage.
Generally, a notebook computer comprises two main sections. The first section is a liquid crystal display (LCD) for displaying information. The second section typically comprises a compact keypad area for entering data.
Notebook computers typically do not use a mouse to perform a cursor scrolling and pointing function. A conventional mouse is comparatively large and has a long cable which must be connected to the computer. This makes it difficult to stow the mouse within the computer without greatly increasing the total size of the notebook computer. Although a separate mouse can be carried by the user and connected to the computer by an external electrical port prior to use, it is inconvenient. Also, since there are typically only a limited number of external electrical ports, attaching an external mouse to a notebook computer limits the number of other peripheral devices which can be attached to the computer. Commonly, notebook computer designers incorporate a touchpad or trackball proximate to the keypad to emulate part of the function of a mouse. The touchpad or trackball performs many of the same scrolling and cursor positioning functions as a conventional computer mouse. However, this is not a satisfactory solution for many applications. For example, while a compact trackball or touchpad emulates some mouse functions, a mouse provides superior control and user comfort for many applications. This is particularly true in graphics applications where the user “clicks” and “drags” line segments to create drawings. A mouse has the advantage that it can be easily moved over a comparatively large area with a high level of control. By way of comparison, a compact trackball or touchpad requires either precise finger motions or slowing the cursor response such that many turns of the trackball or many sweeps across the touchpad are required to change the cursor position across the screen. There are also other problems with notebook computer trackballs and touchpads, particularly if they are used for extended periods. For example, in a constrained location, such as an airline seat, the user may be forced into using the device in a position which is uncomfortable for the user's hand.
Trackballs and touchpads are also an unsatisfactory solution because of the way many businesspeople use their notebook computer. In particular, notebook computers are increasingly being used in sales presentations. High performance notebook computers have excellent graphics capability. Information on product lines and interactive sales presentations can be stored in notebook computers and presented to a group of prospective customers. However, since the best viewing position is directly in front of the computer, the salesperson must position themselves to the side or at a distance from the notebook computer to permit their customers the best view of the screen. Consequently, the salesperson needs to connect an external input device with a long cord if they are to guide the computer presentation. However, the physical size of many external input devices is inconsistent with the goal of a compact, notebook-sized computer which is highly portable (i.e., one that can be easily transported in a salesperson's briefcase). Additionally, separate input devices with long cords have the disadvantage that they can easily become lost, tangled, or damaged during transportation. Moreover, since a notebook computer is extremely light, an input device connected to the notebook computer by a long cable creates the risk that the notebook computer may be accidently dragged to the ground.
One attempted solution to some of these problems is a portable computer design with an internal cavity to house a conventional cable-connected mouse which can be stowed when not in use. For example, U.S. Pat. No. 5,490,039 discloses a portable computer with a mouse designed to be stowed in a cavity in the personal computer. However, the mouse would have to be extremely compact to fit into a notebook computer, which would tend to make it uncomfortable during extended use. Additionally, if the mouse cable was made long enough to facilitate business presentations it could easily tangle or become snagged. Moreover, given the light weight of a notebook computer, a mouse operated from a distance creates the potential for the notebook computer accidentally being dragged by the mouse wire, which may damage the electrical connections or drag the computer off of a table or desk upon which it is placed.
Another attempted solution to some of these problems is a wireless mouse coupled to the computer by electromagnetic means. In particular, the use of an infra-red communications link between a wireless mouse and a computer has been proposed. For example, U.S. Pat. No. 5,726,684 discloses a laptop computer with a detachable mouse-trackball pointing device in which infrared radiation transmission may be used to couple the input device with optical sensors located on the keyboard section of the computer, such as in a cavity in which the pointing device may be stowed when it is not detached from the unit. Similarly, U.S. Pat. 5,049,863 discloses a cursor key unit having a mouse function which may be coupled to the keyboard by optical signals. The cursor key unit pulls out from a cavity in the keyboard section and transmittings optical signals to sensors located in the cavity. However, there are numerous problems with coupling an input device to a notebook computer using infra-red or optical signals. One problem is that common infrared signal sources, such as light-emitting diodes, consume a lot of power. A typical gallium arsenide diode, for example, requires a voltage in excess of 1.5 volts and typically requires a current of one-to-100 milli-amperes to produce a reasonably strong infrared signal. Another problem is that substantial power is needed to a provide a movement sensing function. A wireless mouse incorporating sensors, an infrared source, and control electronics may consume substantial amounts of battery power, particularly if the power of the infrared source is increased such that the mouse can be operated a substantial distance from the optical sensor. Consequently, the battery lifetime of a wireless mouse may be poor, especially if a compact battery is used. A short battery lifetime not only increases the operating cost of the notebook but also increases user frustration. For example, a wireless mouse with a short battery lifetime (e.g., one week) requires a salesperson to bring along extra batteries during a business trip and to proactively change batteries before important presentations.
Another important issue in the design of input devices for notebook computers is ergonomics, which has not been addressed in the context of compact wireless mouse/trackball units. Space and weight are at an extreme premium in a notebook computer. A wireless mouse designed to fit within a cavity in a notebook computer must be extremely compact. However, even small reductions in size of conventional computer input devices may result in the notebook computer being uncomfortable to use. Generally while extensive research has been done on achieving a comfortable hand-grip for conventional mouse designs, the issue of achieving a compact mouse with a comfortable hand grip has not been addressed in the context of wireless mouse designs suitable for notebook computers.
Still another drawback with previously known wireless mouse designs is that they merely replicate the function of a touchpad or trackball integrated into the notebook computer. In particular, conventional wireless mouse designs, such as that of U.S. Pat. Nos. 5,049,863 and 5,726,684, merely permit the user to detach the input device from the keyboard and displace it a short distance in front of the computer. The input device in its detached mode cannot be used to perform functions substantially different from those available in its attached mode. Another reason why previously known wireless mouse designs do not substantially increase the functionality of a computer is that the wireless mouse must be operated within a comparatively short distance of the computer. Since a light emitting diode emits light in a diverging, but predominately line-of-sight mode, the input devices of U.S. Pat. Nos. 5,049,863 and 5,726,684 must be used with the input device disposed substantially pointing towards the sensor located along a portion along the keyboard (i.e., within a keyboard cavity). Thus, the wireless input devices of U.S. Pat. Nos. 5,049,863 and 5,726,684 would not be of much use in locations, such as an airline seat, where the user does not have access to a planar surface directly in front of the keyboard sensor. Also, wireless input devices in which the sensors are configured in a keyboard cavity are completely inconsistent with a salesman using an input device from a distance while a prospective customer sits directly in front of the keyboard, since the customer's body would shield the keyboard sensors from infrared signals. Moreover, the wireless input devices of U.S. Pat. Nos. 5,049,863 and 5,726,684 would require substantial amounts of battery power to be operated at a distance from the keyboard.
Conventional wireless mouse designs provide the limited benefit of permitting the user to operate the input device a short distance directly in front of the keyboard of the computer without an additional cord. However, conventional wireless mouse designs have many limitations, particularly if the unit is reduced in size so that it may be inserted into a cavity in a notebook computer. Consequently, many consumers may decide that the small benefit of a wireless mouse does not justify the additional initial hardware cost, increased maintenance costs (for batteries), and physical discomfort of using a non-ergonomic input device.
What is desired is a new notebook computer and wireless input device design which is energy efficient, consistent with operating the input device an extended distance from the computer, and which increases the functionality available to a user interacting with a notebook computer.